SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3268b42b7f81f3c54dc2a82009d54e1f51bb331c2e120b5f11bd57df58a6918a' 
  AND token = '8gMAKyAVcDX7OQvpWFmYgFNJ0WB6FCNspsoGGcRQPLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}